Shaft-turning device for steam turbines

ABSTRACT

Shaft-turning device for a steam turbine includes an oil turbine having a rotor mountable on the shaft of a steam turbine, and stationary nozzle means for supplying driving medium to the rotor for revolving the same, the rotor having at the outer periphery thereof at least two rows of rotor blades disposed relative to the stationary nozzle means so as to be engageable successively by the driving medium, and guide vane means located between the rows of rotor blades.

United States Patent En elke et a1. Au 5, 1975 [54] SHAFT-TURNING DEVICEFOR STEAM 1,634,894 7/1927 Allen .1 60/704 TURBINES l,678 O67 7/l928Lamb 1 1 1 1 415/1 2.232.852 2/1941 Hemenwuy .1 415/20 [75] Inventors:Wilhelm Engelke; Gerhard Purr, 3341175 6/1941 Bany 4 1 415/20 both ofMulheim (Ruhr). Germany 2,303.190 11/1942 Anderson 1. 415/120 [73]Assignee: Krattwerk Union Aktiengesellschaft. FOREIGN PATENTS ORAPPLICATIONS Mulhelm Germany 189292 1922 United Kingdom .1 60/718 [22]Filed: Aug. 23, 1973 Primary Exa1r1i/1e/'Henry F1 Raduazo [21] Appl'390940 Attorney, Agent, or FirmHerbert L. Lerner [30] ForeignApplication Priority Data [57] ABSTRACT a 7 v 9 Germany 2241788Shaft-turning device for a steam turbine includes an [52] U S Cl us/20.6O/704 415/198 oil turbine having a rotor mountable on the shaft of a[51] d 25/02 steam turbine, and stationary nozzle means for supply-Field l 178 20 ing driving medium to the rotor for revolving the 6458657 b same. the rotor having at the outer periphery thereof at least tworows of rotor blades disposed relative to [56] References Cited thestationary nozzle means so as to be engageable successively by thedriving medium. and guide vane UNITED STATES PATENTS means locatedbetween the rows of rotor blades, 814.423 3/1906 Belluzzo 415/194910,266 1/1909 Belluzzo .1 415/193 4 ClaImS- 4 Drawing F Igures SHEETPATENYEDAUG 5x915 Fig.2

SHAFT-TURNING DEVICE FOR STEAM TURBINES The invention relates to ashaft-turning device for steam turbines, and more particularly to suchdevice having an oil turbine with a rotor secured to the shaft of thesteam turbine, and stationary nozzles for supplying propellant ordriving medium to the rotor.

The present invention is not a turbine as such, but is a shaft-turningdevice for steam turbines, Le. a device which is used to continueturning the steam turbines slowly in order to prevent a distortion ofthe rotor and an uneven cooling after the turbine is shut off. Thisturning device comprises, primarily, two rows of rotor blades separatelymounted on the turbine shaft and an intermediately disposed row of rotorblades, whereby from a segment-shaped nozzle box, which is arranged infront of the first row of rotor blades, oil which is used as the drivingmedium, is supplied to the rows of rotor blades, which starts and/orrespectively keeps, the tur bine shaft turning, depending on the forceof the mass flows.

Such shaft-turning devices have become known heretofore from German Pat.Nos. 975,646 and 1,011,897 wherein there is described a rotor securelymounted on the shaft of the turbine and having rotor blades at the outercircumference thereof while, in axial direction forward of the rotorblades, nozzles for supplying the driving or propellant oil aredisposed. With a shaft device of this type, shafts of great weight canbe accelerated from standstill and possibly turned or rotated forextended periods of time. To turn the shaft and, in particular, to startturning it from a standstill position, however, considerable mass flowsor flow quantities, i.e. large amounts of pressurized oil, are requiredin such a shaft turning device, in order to provide the necessarytorque.

It is therefore an object of the invention to provide a shaft-turningdevice operating with a markedly improved efficiency over that for theheretofore known devices of this general type and which can thereforealso manage with smaller flow quantities.

With the foregoing and other objects in view, there is provided, inaccordance with the invention, a shaftturning device for a steam turbinecomprising an oil turbine including a rotor mountable on the shaft of asteam turbine, and stationary nozzle means for supplying driving mediumto the rotor for revolving the same, the rotor having at the outerperiphery thereof at least two rows of rotor blades disposed relative tothe stationary nozzle means so as to be engageable successively by thedriving medium, and guide vane means located between the rows of rotorblades. Due to this multistate construction, a substantial improvementin the efficiency of the shaft-turning device is provided, because aconsiderably smaller mass flow or flow quantity is required for the sametorque. This means a substantial reduction in the size of the oil tank,the fullload oil pumps on the oil tank with the associated electricmotors, smaller inner diameters for the oil lines and a reduction of thenumber of nozzles in the nozzle housing.

In accordance with another feature of the invention, the shaft-turningdevice includes driving medium sup ply housing means carrying the nozzlemeans and having a part extending in axial direction of the rotor acrossthe width of the rows of rotor blades, the guide vane means beingsecured to the part of the supply housing means.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedinshaft-turning device for steam turbines, it is nevertheless notintended to be limited to the details shown, since various modificationsand structural changes may be made therein without departing from thespirit of the invention and within the scope and range of equivalents ofthe claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of specific embodiments whenread in connection with the accompanying drawings. in which:

FIG. I is an elevational view of the shaft-turning device;

FIG. 2 is an enlarged partial cross sectional view of the rotor and thenozzle housing of FIG. I taken along the line Il-II in the direction ofthe arrows;

FIG. 3 is an elevational view of a nozzle housing with nozzle guidevanes as seen from behind the plane of the drawing of FIG. 1, and

FIG. 4 is a developed longitudinal sectional view of FIG. 3 taken alongthe line IVIV in the direction of the arrows, and including the rotorblades and guide vanes.

Referring now to the drawing and first, particularly, to FIG. 1 thereof,there is shown in a side elevational view of the shaft-turning device ofthe invention, a rotor 2, which carries a row of rotor blades 3 at theouter periphery thereof, and is mounted on a turbine shaft 1. Drivingoil, which drives the rotor, is supplied through two oppositely disposednozzle housings 4 and 5, each of which extends over a peripheral angleof about 60 of the row of rotor blades and is proviced in this regionwith nozzle guide vanes (FIGS. 3 and 4). The nozzle housings 4 and 5 areconnected by feed lines to a non-illustrated oil tank, and to drivepumps.

In the cross-sectional view of FIG. 2, the construction of the rotor 2and the nozzle housing 4 is shown in greater detail. Thus, the rotor 2carries, at the outer periphery thereof, two rows of rotor blades 3 and6, that are disposed in axially spaced relationship to each other. Thenozzle housing 4 has an inner supply duct 7 and corresponding nozzleoutlets provided with guide vanes 8. Between the two rows of rotorblades 3 and 6, there is further disposed a row of guide vanes 9. Theseguide vanes 9 are secured to a part 10 of the nozzle housing 4, whichextends in axial direction of the rotor 2 over the width of the rows ofrotor blades 3 and 6, the guide vanes 9 extending respectively only overthe same peripheral distance as the nozzle outlets 8. The other nozzlehousing 5, not shown in the cross sectional view of FIG. 2, isconstructed in the same manner as the nozzle housing 4.

Due to the disposition of two rows of rotor blades in tandem, as shownin FIG. 2, a considerably greater torque can be obtained with the samemass flow, or flow quantity and the same torque can be obtained with aconsiderably smaller mass flow or flow quantity. Suitable tests haveshown that, with such a twostage construction, torque can be increasedby about 84 percent over a single-stage construction, at the same massflow or flow quantity.

In FIG. 3, a side elevational view of the nozzle housing 5 is providedas seen from the rows of rotor blades.

The individual nozzle outlet vanes 8, which extend over the entirelength of the nozzle outlet are particularly apparent in FIG. 3.

FIG. 4 shows a developed longitudinal sectional view of FIG. 3 takenalong the line lV-IV which passes through the nozzle outlet duct orchannel 7 and the coresponding following rows of vanes 3 and 6. The oilis thus supplied through the duct 7 of the nozzle housing to the nozzleoutlet with the guide vanes 8 and flow therefrom initially into the rowof rotor blades 3. After the oil flows through the row of guide vanes 9secured to the nozzle housing 5, it engages the second row of rotorblades, so that a considerably improved utilization of the mass flow orflow quantity is realizable In this connection it is obvious that, inthe nozzle housing 4 on the opposite side, the guide vanes 8 must becurved in opposite direction. so as to attain the same direction of flowonto the first row of rotor blades.

In the embodiment illustrated in the drawing, it is also possible thatonly one nozzle housing may serve to supply the oil, while the other maybe closed.

ln the illustrated embodiment, a construction with two rows of rotorblades is provided. However, it is also possible within the scope of theinvention to provide more than two such rows of rotor blades in order toobtain an even higher efficiency under the prevailing conditions.

We claim:

l. Shaft-turning device for a steam turbine for continuing to turn thesteam turbine slowly after the steam turbine is shut off, comprising anoil turbine including a rotor mountable on the shaft of a steam turbine,and stationary nozzle means for supplying driving medium to said rotorfor revolving the same, said rotor having at the outer periphery thereofat least two rows of rotor blades disposed relative to said stationarynozzle means so as to be engageable successively by said driving medium,and guide vane means located between said rows of rotor blades, andnozzle means to supply pressurized oil to said rotor blades.

2. Shaft-turning device according to claim I including oil drivingmedium supply housing means carrying said nozzle means and having a partextending in axial direction of said rotor across the width of said rowsof rotor blades, said guide vane means being secured to said part ofsaid supply housing means.

3. Shaft-turning device according to claim 2, wherein said supplyhousing means extends arcuately over a given angle of the peripheryofone of said rows of rotor blades, and carries said guide vanes alongat least part of the length thereof.

4. Shaft-turning device according to claim 3, wherein said supplyhousing means comprises a plurality of nozzle housings located at theperiphery of said rotor.

1. Shaft-turning device for a steam turbine for continuing to turn thesteam turbine slowly after the steam turbine is shut off, comprising anoil turbine including a rotor mountable on the shaft of a steam turbine,and stationary nozzle means for supplying driving medium to said rotorfor revolving the same, said rotor having at the outer periphery thereofat least two rows of rotor blades disposed relative to said stationarynozzle means so as to be engageable successively by said driving medium,and guide vane means located between said rows of rotor blades, andnozzle means to supply pressurized oil to said rotor blades. 2.Shaft-turning device according to claim 1 including oil driving mediumsupply housing means carrying said nozzle means and having a partextending in axial direction of said rotor across the width of said rowsof rotor blades, said guide vane means being secured to said part ofsaid supply housing means.
 3. Shaft-turning device according to claim 2,wherein said supply housing means extends arcuately over a given angleof the periphery of one of said rows of rotor blades, and carries saidguide vanes along at least part of the length thereof.
 4. Shaft-turningdevice according to claim 3, wherein said supply housing means comprisesa plurality of nozzle housings located at the periphery of said rotor.